Grizzly Cartridge makes a WFNGC Hard Cast 180gr .357MAG round, do you think the GP100 can handle that?
Im going to slip into Ruger fanboy mode quick. the real answer to is can you? Seriously you'd really have to overcharge a .357 to put the hurt on a GP-100.

Venom1956: You have a good point. I have shot the a .44MAG with 240gr ammo, so I better be able to handle the 180gr .357MAG.